Medical circumcision

I'm just looking for some advice on the process and recovery. Our 3 year old suffers from UTI`s due to a extermly tight foreskin and has been referred for a circumcision. His penis balloons massively when he pees and as, mentioned gets UTI`s. That cause him alot of pain. Screamimg on the batbroom floor pain. He needs to get this done. I'm just looking for some advice and on what we have ahead of us. Will he go back in nappies do you think?